珠江口盆地白云凹陷古近系源-汇系统耦合及时-空演化  

Source-to-Sink System Coupling and Time-Space Evolution of Paleogene in Baiyun Sag,Pearl River Mouth Basin

作　　者：卫哲 向绪洪 谢世文 张朋霖 单玄龙[3] Wei Zhe;Xiang Xuhong;Xie Shiwen;Zhang Penglin;Shan Xuanlong(CNOOC Deepwater Development Limited,Shenzhen 518054,Guangdong,China;CNOOC China Limited,Shenzhen Branch,Shenzhen 518054,Guangdong,China;College of Earth Sciences,Jilin University,Changchun 130061,China)

机构地区：[1]中海石油深海开发有限公司,广东深圳518054 [2]中海石油(中国)有限公司深圳分公司,广东深圳518054 [3]吉林大学地球科学学院,长春130061

出　　处：《吉林大学学报（地球科学版）》2024年第6期1927-1939,共13页Journal of Jilin University：Earth Science Edition

基　　金：中国海洋石油集团有限公司“十四五”重大科技项目(KJGG2021-0100)。

摘　　要：白云凹陷位于珠江口盆地南部,属于继承性深大凹陷,目前勘探成果表明其为富气凹陷。受控于白云凹陷古近系文昌组和恩平组古地貌格局、断裂组合、物源供给、古沟谷-坡折体系等因素的差异,研究区发育了多个不同类型的源-汇系统。为了明晰研究区内源-汇系统耦合及时-空演化规律,本文通过详细的岩石矿物学分析及三维地震资料对区内核心参数进行了定量化表征。结果表明:裂陷早期(下文昌组时期),物源以盆内基底的中生代中酸性火成岩供源为主,盆地整体呈现了凹隆相间的格局,沉积中心与深洼受NWW和NE向两组不同展布方向的轴向断槽物源控制,并形成了富长英质砂体;该时期的砂体分布范围十分有限,主要呈现短程、低结构成熟度的特征。上文昌组时期,轴向物源逐渐萎缩,受沟谷体系制约的北部物源通道规模逐渐增大,与下文昌组时期相比,该时期碎屑岩具有更高的结构成熟度和成分成熟度,显示了较大规模的搬运过程。恩平组时期,岩相古地理及物源体系格局均与文昌组时期存在明显差异,呈现典型的浅水广盆沉积特征,并在西北通道一侧发育大规模盆外物源,盆内物源区规模明显减小。Baiyun sag is located in southern Pearl River Mouth basin,which is an inherited deep sag.The current exploration results show that it is a gas-rich sag.However,it is controlled by the paleogeomorphology pattern,fault combination,source supply,and paleo-valley-slope break system of the Paleogene Wenchang Formation and Enping Formation in Baiyun sag.There are many different types of source-sink systems in the study area.In this paper,through detailed rock mineralogical analysis and three-dimensional seismic data,the coupling and time-space evolution of the Paleogene source-sink system in Baiyun sag are revealed.In the early stage of rifting(Lower Wenchang Formation),the source was dominated by Mesozoic intermediate-acid igneous rocks in the basement of the basin.The basin as a whole showed a pattern of depression and uplift.The sedimentary center and deep sag were controlled by two groups of axial faults trough sources with different distribution directions in NWW and NE directions,and formed felsic-rich sand bodies.The distribution range of sand bodies in this period is very limited,mainly showing the characteristics of short range and low structural maturity.The axial provenance of the Upper Wenchang Formation gradually shrank,and the scale of the northern provenance channel restricted by the gully system gradually increased.Compared with the Lower Wenchang Formation,the clastic rocks of the Upper Wenchang Formation had higher structural maturity and compositional maturity,showing a large-scale transportation process.The lithofacies paleogeography and provenance system pattern of the Eenping period are obviously different from those of the Wenchang period.It is characterized by the typical sedimentary characteristics of shallow water and wide basin,and large-scale shore-shallow lacustrine facies and braided river delta are developed on the side of the northwest channel.The scale of the source area in the basin is significantly reduced,and the long axis source system outside the basin restricts the distribution of

关 键 词：珠江口盆地 白云凹陷 古近系 物源体系 时空演化 

分 类 号：P618.13[天文地球—矿床学] TE122[天文地球—地质学]